Question

Eight identical cubes of side $4$ cm each are brought together to form a new cube. What will be the total surface area of the new resulting cube?

• A. $768$ cm${}^2$
• B. $384$ cm${}^2$
• C. $572$ cm${}^2$

Answer 1

The correct option is B $384$ cm${}^2$

We have a cube with side $4$ cm



When $8$ such cubes are brought together and stacked, we get a cube like this:


So we see that the new cube has a side of $8$ cm
Therefore, the total surface area of this cube will be $=6\times 8\times 8=6\times 64=384$ cm${}^2$

Option (b.) is correct.